This application claims priority of International application number PCT/DE99/03662 filed Nov. 12, 1999, which in turn claims priority to German patent application number 198 54 038.8, filed Nov. 13, 1998.
The invention relates to a device for detecting the adjustment of translationally moved adjusting devices in vehicles. More specifically, the invention relates to detecting forces of acceleration which act on the vehicle when driving over poor stretches of road.
A process is known from DE 40 20 351 C2 for electronically monitoring and controlling the opening and closing of electrically operated assemblies wherein a setting member is connected to a sensor device which detects adjusting parameters originally linked with the adjusting movement of the setting member. This device is, for example, a sensor which indicates the degree of adjusting movement of a window pane. An additional sensor is installed in the vehicle in order to determine the forces of acceleration acting on the bodywork which were not originally linked with the adjusting movement of the setting member but which are required for triggering an anti-jam protection system to safeguard people and objects from becoming jammed between the window pane and door frame of a vehicle.
The drawback with this solution is that a second separate sensor element with corresponding supply leads and connectors is provided which increases the assembly and material costs.
From DE 196 19 932 A1, an electric motor servo drive is known which recognizes passing through potholes without any additional sensor. In this system, the duration of a revolution of the drive axle changes suddenly and non-uniformly resulting in the triggering of an anti-jam protection device.
The drawback with this solution is that the only forces of acceleration which are detected are those which exist in the adjusting direction. Furthermore, if the adjusting device is not moved, then no information on the forces of acceleration can be obtained.
Furthermore, acceleration switches are known which produce a contact with the occurrence of high accelerations, e.g., in an accident. With these switches, however, no statement on the degree of acceleration is possible since it is only determined that a boundary value is exceeded.
The object of the present invention is to provide an apparatus, with a small structural expense, which obtains as much information as possible on the adjusting movement of translationally movable adjusting devices and the forces acting on the vehicle.
According to the invention, vehicle acceleration information can be obtained without having to provide an additional sensor device. Thus, structural elements which are already present can be utilized to optimum effect. As a result, a sensor device which detects the rotary movement of an adjusting drive in order to slow down or switch off the drive upon reaching a certain position, can also detect the vibrating movement of a vehicle when driving over poor stretches of road. This information is of special importance for triggering an anti-jam protection device since the set trigger criteria can be falsified by the additional forces of acceleration.
Likewise, transverse accelerations when driving fast around bends can be determined. This data can be used for fixing the boundary values of the anti-jam protection or supplied to other control devices to, for example, influence an active chassis or brake control. It is likewise possible to determine severe acceleration or deceleration of the vehicle.
A further area of use of the present invention is in detecting the vibration of the adjusting drive. Driving off or starting up the engine can lead to vibration movements as a result of the breakaway forces and start-up torques which have to be overcome. With the present invention, it is possible to determine the start-up conditions which are based on external influences such as temperature or dampness. It is thus possible to, for example, standardize the threshold value for an anti-jam protection since, with stronger start-up vibrating movements, it is possible to determine a greater resistance such as a greater friction resistance of the adjusting device, so that the threshold value is correspondingly adjusted.
A quantitative evaluation of the vibrating movement is likewise possible. For example, based on the extent of the vibrating movement, it becomes possible to draw conclusions relating to the resistances in the adjusting device, for example, the wrong or correct installation, wear, or optimum operating conditions.
If the sensor detects the forces of acceleration acting on the vehicle in the direction of the adjusting movement, then the extra force acting on the adjusting device can be determined, and the threshold value of the anti-jam protection can be adjusted with less expense.
In one embodiment of the invention, the sensor includes several sensor elements associated with each other. For example, a first sensor element is connected to the adjusting device or to a drive for the adjusting device, and a second sensor element associated with the first sensor element is mounted independently of the first sensor element.
The present invention enables a determination of the forces which act on the vehicle when at least one of the sensor elements is supported resiliently directly on the vehicle chassis, or through the adjusting device or drive of the adjusting device on the vehicle chassis. If lasting or permanent displacements occur between the sensor elements, for example, following an accident, then it is possible to determine the displacement and, therefore, changed signal, about the effectiveness of the adjusting device and the degree of accident damage.
For reasons of minimizing wear and optimum detection of forces additionally acting on the vehicle, it is advantageous to mount the sensor elements substantially without contacting one another.
In a further development of the invention, a signal-transmitting sensor element (transmitter) sends a signal with constant amplitude and/or frequency. The amplitude and/or frequency changes detected by a signal-receiving sensor element (receiver) represent a function of the forces acting on the vehicle.
Preferably, the signal-transmitting sensor element has at least one partition with two sections of different signal levels. The signal-receiving sensor element is positioned relative to the signal-transmitting sensor element so that signals emanating from the sections of different signal levels and signal changes based on the displacements of the signal-transmitting sensor element and/or signal-receiving sensor element are detected. As a result, relevant adjusting movements and the acting forces can be simply and reliably detected.
In an another aspect of the invention, the circuit arrangement for evaluating the sensor signals sends an acceleration signal when the amplitude and/or frequency changes detected by the signal-receiving sensor element exceed a predetermined threshold value.
The circuit arrangement for evaluating the sensor signals has an amplifier connected to the output of the signal-receiving sensor element. The output of the amplifier is connected to the input of a first comparator. The other input of the comparator is attached to a first reference voltage source which corresponds to the predetermined threshold value of the amplitude change and at whose output the acceleration signal appears.
In a variation of the invention, a sensor determines the speed and/or rotary direction of the drive of the adjusting device through a signal transmitter connected to the drive shaft. A signal receiver is associated with the signal transmitter. The transmitter and receiver are mounted movable relative to each other and configured such that the signal receiver detects the relative movement between the signal transmitter and the signal receiver. The signal receiver sends sensor signals corresponding to the relative movements to the circuit arrangement.
This arrangement can be achieved if the signal transmitter is supported on the drive shaft elastically displaceable in the axial direction about a rest position, and the signal receiver detects the axial displacement of the signal transmitter. Alternatively, the signal transmitter can be fixed or connected to the drive shaft, and the drive shaft is mounted elastically displaceable in the axial direction about a rest position. It is also possible, however, for the signal receiver to be mounted elastically displaceable about a rest position in the axial direction of the drive shaft and/or perpendicular to the drive shaft.
In order to permit only certain movements of the signal receiver, for example, to fix the movements about a maximum deflection or to superimpose directions of movements, the signal receiver is designed displaceable along a guide path.
In one embodiment, the signal transmitter is formed from a ring magnet or a cylindrical multi-pole magnet. The signal receiver is formed from a Hall sensor aligned with the ring magnet or the sleeve face of the multi-pole magnet.
As an alternative embodiment, the sensor is constructed based on a magneto-resistive effect. A transmitter is formed as a cylindrical multi-pole magnet, and a receiver is formed as a magneto-resistive sensor. The receiver is aligned with the cylinder face of the multi-pole magnet.
In a further embodiment, an inductive sensor is provided with a signal transmitter e.g., a cylindrical magnetic disc, which rotates between the poles of a metal fork. An induction coil mounted on the metal fork serves as a signal receiver. Through the rotation of the magnet, a voltage is induced in the induction coil which changes in dependence on the movement of the disc relative to the fork.
In yet another embodiment, an opto-electronic sensor is utilized. The opto-electronic sensor includes a punctured or slit disc, a light-emitting element aligned with the end side of the punctured or slit disc, and a signal transmitter, preferably a photo-diode. In the reflection area of the rays reflected by the punctured e.g., or slit disc, a light-receiving element is provided as a signal receiver, preferably a photo-transistor. If the disc is displaced, only a part of the rays transmitted by the photo-diode is reflected. As a result, a corresponding change in the output signal of the photo-transistor is produced.
If the sensor is constructed as a capacitor, a part of the sensor device includes a rotating metal disc. The metal disc includes alternating regions of different dielectric constants, and a metal plate partially covering the circular surface of the metal disc.
In order for the adjusting drive or sensor device to have the greatest possible freedom with regard to the alignment of the axes of movement, a two-sided swivel lever with a vibrating mass is mounted on the lever arm remote from the signal transmitter. The lever arm is associated with the signal transmitter so that the signal transmitter is moved axially corresponding to the vibration of the mass. The lever is formed on the signal transmitter side as a fork which engages around the signal transmitter to allow displacement in both axial directions.